The biggest complaint about the original MyWi was that it was a battery killer. I think that's understating the case. The app could kill batteries even while plugged into a power source. Now, I'm not saying that MyWi is now suddenly a kinder, gentler, non-battery consumer when actively serving connections to other devices, but it has a killer new approach to providing that connectivity with a low-power always-on mode.
The new MyWi introduces Bluetooth on-demand tethering. Wi-Fi is always scanning for a base station to connect to and can then automatically connect to it if you've chosen that as a known and trusted host. Intelliborn's always-on Bluetooth implementation performs a similar kind of search. When it finds a MyWi Bluetooth hotspot, it can automatically connect to that service. And, like Wi-Fi, that service has almost a zero battery footprint, so being ready to connect at all times takes up very little power consumption.
To take advantage of this new feature, you'll need to have the software installed on both the host device as well as the client one, which means jailbreaking both. Of course, you can still use MyWi in classic mode, without having to jailbreak a second unit, but that limits you to Wi-Fi only use. Because of its battery demands, the Wi-Fi mode will now automatically shut off after an idle period.
As you can see from the video, the updated software is also a lot prettier than it used to be. I haven't had a chance to test it out yet, but the video makes me want to.
MyWi is available through the Cydia store and costs US$24.99, or $4.99 for owners of MyWi 4.0.